Field of the Invention
The present invention is related to the area of semiconductor inspection systems, and particularly related to techniques for yield management in semiconductor inspection systems. More particularly, an electron beam inspection system includes multiple stages or multiple chambers, where the chambers/stages (N≥2) are organized to form one or more paths for wafer/mask inspection. An inspection procedure in each chamber (or at each stage) is determined by its order in the path and the relative columns used. For a system with N chambers/stages, a maximum number of N wafers/masks can be processed simultaneously.
Description of the Related Art
Inspection systems help semiconductor manufacturers increase and maintain integrated circuit (IC) chip yields. Semiconductor manufacturers buy the inspection systems at a rate of close to US$1B per year. This capital investment attests to the value of the inspection systems in manufacturing IC chips. The IC industry employs the inspection systems to detect various defects that may have occurred during the manufacturing process. One of the purposes provided the inspection system is to monitor whether the manufacturing process is under control. If it is not, the system could help indicate the source of the problem. The important characteristics of an inspection system are defect detection sensitivity and throughput. The sensitivity and throughput are often related, as in general greater sensitivity usually means lower throughput.
Evolution of the semiconductor manufacturing industry is placing ever greater demands on yield management and in particular, on metrology and inspection systems. Critical dimensions are continuously shrinking while wafer size is increasing from 200 mm to 300 mm or possibly more in the future. Economics is driving the industry to decrease the time for achieving high-yield, high-value production. Thus, minimizing the total time from detecting a yield problem to fixing it determines the return-on-investment for the semiconductor manufacturers.
Thus there is a great need for methodologies or inspection systems that are adaptive enough to provide the most efficient yield management.